The invention relates to variable reluctance magnetic speed sensors, for example for sensing the speed of a rotating gear.
Magnetic speed sensors are known in the art, and operate on the principle of a changing magnetic field producing a voltage signal. The approach and passing of a discontinuity, such as a gear tooth, changes the magnetic field, which change induces a voltage in a coil. An example is shown in Electro Corporation Catalog Nos. 83AS103 and 83AC100, 1983, and A Technical Applications Handbook, "Sensing and Controlling The Industrial World", Electro Corporation, 1981.
The present invention relates to improvements in magnetic field flux coupling for greater sensitivity.